SCAN TEST DEVICES WITH 18-BIT UNIVERSAL BUS TRANSCEIVERSThe ABTH18502A and ABTH182502A scan test devices with 18-bit universal Bus Transceivers are members
of the Texas Instruments SCOPE testability integrated-circuit family. This family of devices supports IEEE
Standard 1149.1-1990 boundary scan to facilitate testing of complex circuit-board assemblies. Scan access to
the test circuitry is accomplished via the 4-wire test access port (TAP) Interface
In the normal mode, these devices are 18-bit universal Bus Transceivers that combine D-type Latches and D-type
Flip-Flops to allow data flow in transparent, latched, or clocked modes. They CAN be used either as two 9-bit
transceivers or one 18-bit transceiver. The test circuitry CAN be activated by the TAP to take snapshot samples
of the data appearing at the device pins or to perform a self test on the boundary-test cells. Activating the TAP
in the normal mode does not affect the functional operation of the SCOPE universal Bus Transceivers
Data flow in each direction is controlled by output-enable (OEAB and OEBA), latch-enable (LEAB and LEBA),
and Clock (CLKAB and CLKBA) inputs. For A-to-B data flow, the device operates in the transparent mode when
LEAB is high. When LEAB is low, the A-bus data is latched while CLKAB is held at a static low or high Logic level.
Otherwise, if LEAB is low, A-bus data is stored on a low-to-high transition of CLKAB. When OEAB is low, the
B outputs are active. When OEAB is high, the B outputs are in the high-impedance state. B-to-A data flow is
similar to A-to-B data flow but uses the OEBA, LEBA, and CLKBA inputs.
In the test mode, the normal operation of the SCOPE universal Bus Transceivers is inhibited and the test circuitry
is enabled to observe and control the I/O boundary of the device. When enabled, the test circuitry performs
boundary-scan test operations according to the protocol described in IEEE Standard 1149.1-1990. By Texas Instruments
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SN54ABTH182502A Pb-Free | SN54ABTH182502A Cross Reference | SN54ABTH182502A Schematic | SN54ABTH182502A Distributor |
SN54ABTH182502A Application Notes | SN54ABTH182502A RoHS | SN54ABTH182502A Circuits | SN54ABTH182502A footprint |